1. Home
  2. Engines
  3. Harbor Freight Engines
  4. Predator 420 Engines
  5. Camshafts
  6. 310 Camshaft - Honda GX390/Big Block Clone
310 Camshaft - Honda GX390/Big Block Clone
.310 Lift Camshaft - Honda GX390/Big Block Clones
Write a Review

310 Camshaft - Honda GX390/Big Block Clone

Part Number: 310-GX390
Online Price: $149.99
DynoCams 310 Camshaft for Honda GX390 & Big Block Clone Engines
Availability: In Stock.

Send to:

*We'll ask for shipping info at checkout

Description

DynoCams 310 Camshaft – Honda GX390 & Big Block Clone Engines


The DynoCams 310 Camshaft is a purpose-built low-lift, long-duration racing camshaft engineered for high-RPM Honda GX390 and big block clone engines. While lift remains a modest .310", the increased duration shifts peak torque and horsepower higher in the RPM range and allows the engine to carry power further on the top end—making it an ideal choice for aggressive modified racing applications.


The .310 profile is specifically designed to work with 1.2 or 1.3 ratio rocker arms, allowing most modified cylinder heads to be configured for approximately .400” total valve lift without compromising valvetrain stability.


Performance Characteristics

Compared to the popular .308 camshaft, the DynoCams 310 offers similar lift but substantially more duration, resulting in increased power at higher engine speeds. The gains are most noticeable when paired with ported cylinder heads and larger valves, where airflow improvements allow the cam’s extended duration to fully translate into usable horsepower.

This camshaft is best suited for racing engines operating above 5,000 RPM. Due to the increased overlap, idle quality will be noticeably rougher—especially when combined with ratio rockers and larger carburetors—making this cam unsuitable for mild or non-racing applications.


Built for Durability

The DynoCams 310 Camshaft features a hard-welded lobe design that significantly improves wear resistance in high-RPM, high-spring-pressure environments. Because of the cam’s aggressive profile, upgraded dual valve springs are mandatory to maintain proper valvetrain control and long-term reliability.


Recommended Supporting Components

To fully realize the performance potential of the DynoCams 310 Camshaft, the following components are strongly recommended:

  • 34mm Carburetor
  • Billet Connecting Rod
  • Billet Flywheel
  • Billet Rocker Arms
  • Chromoly Pushrods
  • Big Valves & Porting
    Larger valves and professional port work raise the effective power band and significantly extend top-end horsepower. Big block engines naturally produce strong low-end torque, so increased airflow does not negatively affect bottom-end performance.


Fitment

  • Honda GX390
  • Predator 420 Wedge (Non-Hemi)
  • Wildcat 460
  • Cam Boss: 16mm(.628”)

Important: Camshaft-to-block and camshaft-to-rod clearance must be inspected during installation.



Technical Specifications

Engine Platform: Honda GX390 / Big Block Clone
Recommended Class: Modified
Target Maximum RPM: 7,500 RPM
Valve Spring Pressure (Intake / Exhaust): 50–55 lbs Dual Springs
Valve Lash (Intake / Exhaust): .003"

Ignition Timing Recommendations

  • Pump Gas: Not Recommended
  • Race Gas (110 Octane): 32° BTDC
  • Methanol: 36° BTDC

Recommended Compression Ratio: 12:1


Camshaft Timing & Lift Specifications

Specification

Intake

Exhaust

Open

57.15° BTDC

96.10° BBDC

Close

95.30° ABDC

57.95° ATDC

Lift

.309"

.309"

Centerline

108.0° ATDC

108.0° BTDC

Duration @ .050"

255.00°

259.95°

Duration @ .200"

158.50°

164.50°

Why Choose the DynoCams 310?

  • Long-duration racing cam for high-RPM GX390 builds
  • Optimized for ported heads and big valves
  • Designed for ratio rocker arm configurations
  • Hard-welded for extreme durability
  • Proven performance in modified racing classes

FAQ

What is the DynoCams 310 camshaft best used for?

The DynoCams 310 camshaft is designed for high-RPM racing applications using Honda GX390 and big block clone engines. It performs best in modified builds operating above 5,000 RPM with upgraded valvetrain components.


How does the 310 camshaft compare to the 308 cam?

The 310 cam has similar lift to the 308 but significantly more duration. This moves peak torque and horsepower higher in the RPM range, making the 310 better suited for ported heads, big valves, and aggressive racing setups.


Can the DynoCams 310 cam be used with ratio rockers?

Yes. The .310 lift profile allows the use of 1.2 or 1.3 ratio rocker arms, enabling many modified cylinder heads to achieve approximately .400” total valve lift.


Is the DynoCams 310 camshaft street-friendly?

No. Due to its long duration and overlap, idle quality is rough and low-RPM performance is reduced. This camshaft is intended strictly for competition and racing use.


What supporting upgrades are required?

Upgraded dual valve springs are mandatory. A billet connecting rod, billet flywheel, ratio rockers, chromoly pushrods, and a 34mm carburetor are strongly recommended for reliability and performance.


What engines does the DynoCams 310 camshaft fit?

The DynoCams 310 camshaft fits Honda GX390, Predator 420 Wedge (Non-Hemi), and Wildcat 460 big block clone engines.


Does this camshaft require clearance checking?

Yes. As with all high-performance camshafts, cam-to-block and cam-to-rod clearance must be inspected during installation.

Related Items

315 Camshaft - Honda GX390/Big Block Clone
$149.99
Out of Stock.

Recently Viewed Items

Logo